An electric vehicle, also referred to as an electric drive vehicle, is a moving vehicle using one or more electric motors as driving system. Unlike petroleum-based transportations which are moved by the energy from gasoline, the electric vehicles use electric power as their propulsion. They won't generate waste gas. Noise is also less. During the last few decades, increased concern over the environmental impact of the petroleum-based transportation, along with the spectre of peak oil, has led to renewed interest in electric transportation. Electric power for electric vehicles can be generated from a wide range of sources, including fossil fuels, nuclear power, and renewable sources such as tidal power, solar power, and wind or any combination of those.
In the past, an electric vehicle consumes huge electric power due to their power system. The electric power can only be transmitted to the car through overhead lines. This infrastructure makes the electric vehicles impossible to be popular. Only some of public transportations have access to it. Routes of the public transportation are strictly limited by the lined arrangement. With the development in power systems of electric vehicles, especially in batteries, the electric vehicles become a future star and more and more sources are devoted in this field.
People are used to their existing life experience. Hence, a system for charging the batteries of the electric vehicles should be as convenient as a gas station system. When batteries of an electric car are in low battery, people can drive the car to a nearby charging station and get the batteries charged or replaced with full charged ones. Preferably, the batteries can be charged during off-peak period when cost of charge of electricity is lowest. Meanwhile, with a device to manage batteries that are used in the car, people can always know the status of the batteries and mechanics of the stations can trace the batteries for maintenance. Since the batteries are expensive, if the batteries are stolen and they can be easily found, it will be a great help for the car owners. However, the requirements mentioned above need an integrated system to fulfill.
U.S. Pat. No. 7,679,366 discloses a method for recharging an electric storage battery in a charging system of an electric vehicle. Please refer to FIG. 1. Power comes from an electric utility power grid. '366 Patent includes determining the length of time required to recharge the battery, determining the desired time when the recharge is to be completed, transmitting to the electric power utility the length of time required to recharge the battery and the desired time, and recharging the battery from the utility grid during a period when projected load demand is lower than peak demand and ending no later than the desired time.
'366 Patent is for hybrid electric vehicles, not for pure electric vehicles. The method only focuses on an optimal way to charge the batteries through a day so that time for low demand of electricity can be fully applied and charging cost can be minimal. However, no solution for battery management is mentioned.
Another prior art is disclosed in U.S. Pat. No. 7,795,841. Please refer to FIG. 2. '841 Patent provides a charging system and method capable of starting or stopping charging a battery of a vehicle at a convenient time. A portable device and a vehicle unit can communicate with each other. A user is determined to be away from the vehicle based on a result of communication between the portable device and the vehicle unit. A charging ECU starts charging a battery when the user is away from the vehicle. Charging of the battery can be started when the user is assumed to have stopped using the vehicle and will not use the vehicle for a period of time. When the user is determined to be close to the vehicle it is assumed that use of the vehicle will be resumed at which point the system instructs the charging of the battery to be stopped. The system allows the vehicle to be ready for use.
'841 Patent is also applied to hybrid electric vehicles. It uses the portable device to control the process of charging. However, the portable device can not inform the user of charging or battery status. Charging schedule can not be set to utilize off-peak time of electric power source to save cost.
None of the prior arts can provide an integrated system and method for charging the electric vehicle using a smart card for battery management when charging the battery, preventing the batteries from being stolen, or save charging expense for users. Hence, an integrated system and a method for charging electric vehicles having above features are still desired.